This invention relates to a connection assembly. More specifically this invention relates to a gear shift connection apparatus for a tiltable, over-the-engine, tractor cab.
In the trucking industry the tractor portion of a tractor trailer combination is often designed with the cab mounted on top of the tractor engine and transmission. Such a design, among other things, minimizes the overall length of the rig and is in widespread and popular use.
In order to service and/or work on the engine of such a tractor design the cab is tilted upward to expose the engine and drive train. At least one illustration of such a unit may be found by reference to U.S. Pat. No. 3,761,123 to Neill et al and of common assignment with the subject application. In this patented design a hydraulic cylinder is utilized to tilt the cab from a normal horizontal position to a tilted posture as depicted in FIG. 1 of the patent.
In order to lock the cab in a normally lowered operating position the present applicant has invented a noval hydraulic coupling which forms the subject matter of a copending application Ser. No. 696,591 entitled LATCHING MECHANISM now U.S. Pat. No. 4,082,342.
A significant problem with tractors having an over-the-engine cab design is that the gear shift rod which is connected to the gear box, must also project into the cab adjacent an operators station. When the tractor cab is tilted upwardly for service some provision must be made to accommodate the gear shift rod.
One solution to the gear shift problem entails providing a slot in the cab floor so that the shift rod will pass through the slot when the cab is tilted forward. Leather or rubber sealing strips are fitted along each side of the slot to reduce engine noise and prevent dust and cold air from blowing into the cab. These strips, however, are considered only marginally effective in a new condition and in a worn or used condition typically do not function in an acceptable manner.
Another previously know design provides a mechanical telescopic coupling between a gear shift rod and a gear box. When the cab is tilted forward the connection telescopes outwardly. At least one difficulty with such a design is that it is somewhat mechanically complicated, expensive to initially install and maintain and subject to fouling and jamming.
The difficulties suggested in the preceeding are not intended to be exhaustive, but rather are among many which may tend to reduce the effectiveness of prior designs for accommodating a gear shift rod in an over-the-engine cab. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that designs appearing in the past will admit to worthwhile improvement.
It would be desirable to provide a connection assembly wherein the gear shift rod could be reliably released from connection to the tractor chassis when the cab is tilted forward and reconnected to the chassis when the cab is lowered again. Additionally it would be highly desirable to provide a connection system which is automatic in operation and does not require special operator attention or consideration.